1. @chrispacia - Lead backend dev OpenBazaar
How to Leverage Libp2p for blockchain applications
@chrispacia - Lead backend dev OpenBazaar

2. What

3. Common Needs Identity Peer discovery Routing
Wire encryption/authentication
Multi-transport
Nat traversal
Stream/protocol multiplexing
Relaying
Common Needs

4. Languages

5. Architecture Transport agnostic
transports: TCP, UDP, SCTP, UDT, uTP, QUIC, SSH, etc.
authenticated transports: TLS, DTLS, CurveCP, SSH
Architecture

6. Multiaddr Support addresses for any network protocol.
Are self-describing.
Conform to a simple syntax, making them trivial to parse and construct.
Have human-readable and efficient machine-readable representations.
Encapsulate well, allowing trivial wrapping and unwrapping of encapsulation layers.
/ip6/fe80::8823:6dff:fee7:f172/tcp/4001
/ip4/ /udp/4001/utp
/onion/erhkddypoy6qml6h:4003
/ip6/2601:9:4f81:9700:803e:ca65:66e8:c21/udp/1234/quic
Multiaddr

8. Multihash Format Examples
<varint hash function code><varint digest size in bytes><hash function output>
Examples
# sha1 - 0x11 - sha1("multihash") c2f11fb2ce392acb5b2986e640211c e # sha1 in hex CEKIRQXRD6ZM4OJKZNNSTBXGIAQRYRUQA47A==== # sha1 in base32 5dsgvJGnvAfiR3K6HCBc4hcokSfmjj # sha1 in base58 ERSIwvEfss45KstbKYbmQCEcRpAHPg== # sha1 in base64 # sha x12 - sha2-256("multihash") cbc07c3f a3aa2a581ca aa420b9d99bc0e131d9f3e2cbe47 # sha2-256 in hex CIQJZPAHYP4ZC4SYG2R2UKSYDSRAFEMYVJBAXHMZXQHBGHM7HYWL4RY= # sha256 in base32 QmYtUc4iTCbbfVSDNKvtQqrfyezPPnFvE33wFmutw9PBBk # sha256 in base58 EiCcvAfD+ZFyWDajqipYHKICkZiqQgudmbwOEx2fPiy+Rw== # sha256 in base64
Multihash

10. Architecture Multiplexing
can multiplex multiple listen network interfaces
can multiplex multiple transport protocols
can multiplex multiple connections per peer
can multiplex multiple client protocols
can multiplex multiple streams per protocol, per connection (SPDY, HTTP2, QUIC, SSH)
has flow control (backpressure, fairness)
encrypts each connection with a different ephemeral key
Architecture

11. Protocol Muxing

12. Architecture Encryption Communications on libp2p may be: encrypted
signed (not encrypted)
clear (not encrypted, not signed)
Architecture

14. Architecture Nat Traversal / Relay Multiaddr Format
[<relay peer multiaddr>]/p2p-circuit/<destination peer multiaddr>
Examples
/p2p-circuit/p2p/QmVT6GYwjeeAF5TR485Yc58S3xRF5EFsZ5YAF4VcP3URHt - Arbitrary relay node
/ip4/ /tcp/5002/p2p/QmdPU7PfRyKehdrP5A3WqmjyD6bhVpU1mLGKppa2FjGDjZ/p2p- circuit/p2p/QmVT6GYwjeeAF5TR485Yc58S3xRF5EFsZ5YAF4VcP3URHt - Specific relay node
Architecture

15. Routing
Kademlia DHT
Supernode
MDNS
Other
Architecture

16. Routing Lightning Network Libp2p
Libp2p
QmYMR9kDCSF3yBVVyhsRepJC4Byx6TrYGbjZsBgzVP9rG2 [ “/ip4/ /tcp/4001”,
“/ip4/ /tcp/9005/ws”
“/ip4/ /tcp/4001”,
“/ip4/ /tcp/4001/ws”,
“/ip6/::1/tcp/4001”,
“/ip6/::1/tcp/9005/ws”,
“/ip6/Fe80::8823:6dff:fee7:f172/tcp/9005/ws”,
“/onion/erhkddypoy6qml6h:4003” ]
Routing

17. Pubsub
Propagate information throughout the network in a structured manner, with or without guarantees
like: order, delivery, efficiency, fault tolerance and so on.
floodsub
multicast
Architecture

18. Identity
DHT
Protocol multiplexing
Wire encryption
Pubsub
Example

19. Further Reading https://libp2p.io/ https://github.com/libp2p
@chrispacia
Further Reading